Commercial tilapia farming is limited almost exclusively to the culture of three species: Oreochromis niloticus, O. aureus, and O. mossambica. Of the three tilapia species with recognized aquaculture potential, the Nile tilapia, O. niloticus, is by far the most commonly cultured species. The use of hybrids of 2-4 species of tilapia is also quite popular in certain countries.
Production strategies for tilapia range from the simple to the very complex. Relatively simple tilapia farming strategies are characterized by little control over water quality and food supply and by low fish farm yields. As greater control over water quality and fish nutrition is imposed and fish stocking levels are increased, the fish yield per unit area increases. Across this wide range of fish farming methods, there is a progression from low to high management intensity.
In traditional pond culture of tilapia, proper environmental conditions are maintained by balancing the inputs of feed with the natural assimilative capacity of the pond environment. The pond’s natural biological productivity (algae, higher plants, zooplankton and bacteria) serves as both a food source and a biological filter that helps convert fish waste by-products through natural biological processes. Increasing fish stocking densities places increasing demands on the fish production system. Additional inputs in the form of labor, water exchange, aeration, and higher quality fish feeds are all required to sustain tilapia culture conditions in intensive systems. As pond production intensifies and fish feeding rates increase, supplemental aeration and some water exchange are required to maintain good water quality. For fish stocking densities above 1.5-kg per square meter, aeration is usually required. Eventually, there is an endpoint where the incremental returns on investment are not worth the incrementally higher rates of production relative to the higher costs and higher risks. In other words, increasing the intensity of the fish culture system does not necessarily reflect an increase in profitability.
All tilapia production systems must provide a suitable environment to promote the growth of the fish. This is true regardles of whether tilapia are grown in ponds, cages, or in tanks. Critical environmental parameters that must be properly managed include dissolved oxygen and unionized ammonia. Other important parameters to control within the fish production system include nitrates, pH, and alkalinity. To produce tilapia in a cost effective manner, aquatic production systems must be capable of maintaining all of these water quality variables in a safe range for the entire grow-out period.
Proper feeding of a nutritionally balanced feed is critical to the success of any tilapia farming operation. To produce excellent growth rates, tilapia are typically fed moderate to high protein diets at rates ranging from 1.0% to 30% of their body weight per day, depending upon the age and size of the fish.
Numerous options for holding broodfish, fry, fingerlings, juveniles, sub-adult and adult tilapias are available to the prospective farmer. The basic options include ponds, tanks or raceways, and cages. Ponds are used in extensive, semi-intensive and intensive tilapia production. Pond culture is the most common method of growing tilapia. Ponds are comparately cost effective to build and have the advantage of utilizing the natural productivity associated with ponds. One potential drawback of pond culture is the greater risk of uncontrolled reproduction, which will occur if the tilapia have not been properly sex-reversed prior to stocking. Tanks or raceways require higher capital expenditure, but do offer greater control ofthe fish production system. Tanks are typically used in intensive growout of tilapia and in tilapia hatcheries. Cage culture is also a cost effective method of farming tilapia when suitable sites are available. Cage culture does have unique risks such as escapement and critically low dissolved oxygen events due to lake turnover.
